Drill-chuck



(No Model.)

J. T. BASTOW. DRILL CHUCK No. 465,826. Patented Dec. 29, 1891.

- Wilma-mam jru/eiufor QW (7% f fimw/ I 1 60w I UNITED STATES! PATENT OFFICE.

JOHN T. BASTOIV, OF CLAYVILIJE, NEIV YORK.

DRILL-CHUCK.

SPECIFICATION forming part of Letters Patent No. 465,826, dated December 29, 1891.

Application filed May 11, 1891. Serial No. 392,346. (No model.)

To aZZ whom it may concern:

Be it known that I, JOHN T. BASTOW', a citizen of the United States, residing at Clayville, in the county of Oneida and State of New York, have invented certain new and useful Improvements in Drill Chucks; and I do hereby declare the followin g to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The special object of the invention is to improve that class of drill-chucks which center a twist-drill with jaws that close upon it in the usual way, but prevent it from slipping when at work by securing a rabbeted upper end or tang in some manner.

My invention consists in the particular means by which I rigidly secure the upper end of the drill.

Figure 1 of the drawings is a vertical section of a drill-chuck containing my invention and showing its position, and Fig. 2 a detail View of the screw-plug holding the tang of the drill-shank.

In the drawings, A represents my plug, which is provided with a left-hand thread, is tapered from the upper to the lower end to fit the chuck-opening B, and is made with the diametrical open slot D at the lower end to receive the tang E of the drill-shank. The hub C is threaded in the lower part or wall of the chuck-opening B, so as to correspond with the thread 011' the exterior face of the plug A.

In order to screw the plug home in its socket b, it is first let down into the opening B and the'drill-tang E inserted in the slot D.

The drill-shank is then turned to the rightuntil the plug is f ullyseated and can advance no farther downward. clamped by the jaws F, which may be two or more in number, and is ready for use to be still turned in the same direction. In order to remove the plug from its seat 11 the jaws F are retracted and the drill turned in a reverse direction. Thus it will be seen that the plug is put in and taken out by the drill, while it is utterly impossible for the drill 'to slip. In this way the strain is taken almost entirely from the centering-jaws;

hat I claim as new, and desire to protect by Letters Patent, is'

JOHN T. BAs'row.

Witnesses:

THOMAS E. BEVAN, WVILLIAM MURRIN.

The drill is then 

